If I am going to be quilting it very soon I'll use an air erasable marking pen.
If there is going to be a wait til I quilt it I might use a clear vinyl overlay and draw my design then get back to mark it just before quilting it.
Of course there is also Golden Threads ... they have a paper just for this. You draw your design with whatever [I'd still use a type of marking pencil, but that is just me - never a ball point or regular ink pen as that ink can really smear.] Pin it to the quilt and then follow the lines almost like PP.
ali